Autonomy is the most important and innovative notion of Kant’s practical philosophy. It is also one of the most mysterious and difficult. Bacin’s impressive book offers a novel interpretation of Kantian autonomy, faithful to the text of Kant’s published works, which it often integrates with student notes and Kant’s private notes, and attentive to the philosophical context of Kant’s reflection.

Chapter one shows how Kant’s criticisms of moral rationalist theories in notes prior to the Groundwork play a decisive role in the development of his doctrine of autonomy. Kant’s inclusion of both perfectionist and theological voluntaristic theories in the rationalist field, Bacin argues, let him dismiss the most simplistic versions of divine command theory from the outset, as based on empirical rather than rational knowledge. Kant’s main criticism to perfectionism is that its prescriptions are ‘tautologies’ (36),Footnote ¹ while he devotes much more effort to criticizing the voluntaristic conception of morality. According to Bacin, Kant’s four main objections against the latter point to the fundamental criticism that even more sophisticated versions of voluntarism are, upon closer inspection, based on empirical elements.

Kant’s objections to moral rationalism, Bacin continues, do not impugn the rationalist conception of reason as the faculty of non-empirical truths, and Kant effectively develops ‘a new rationalist explanation of morality’ (46), linked to both rationalist approaches. According to Kant, although perfectionism is superior to voluntarism, it still cannot adequately account for the bindingness of moral laws. The reason is that it cannot involve a legislative act of the author of moral obligations, and instead treats the will merely as the addressee of obligations. In this respect, Kant agrees with voluntarism that a valid law requires a legislator endowed with authority; however, in his view, this legislator is every rational will. This move, Bacin warns, is not a mere ‘[substitution of] the divine will with an alleged semi-divine “transcendental subject”’: rather, Kant’s original synthesis of the two rationalist approaches reaches the notion of ‘a rational will which, under the constraint of a constitutive standard, operates through universal volitions’ (52, emphasis added). While incomplete in some respects, Bacin concludes, Kant’s doctrine of autonomy as a ‘two-level notion’, uniting ‘a law that is necessary and not positive’ and ‘the legislating function of the rational will’ (55), is already suggested by his critical assessment of rationalist theories of morality prior to the Groundwork.

At the beginning of chapter two, Bacin (somewhat cursorily) criticizes some Kantian attempts to defend the notion of self-legislation from the traditional charge of incoherence and then expands on his interpretation of autonomy as a two-level notion. He begins by commenting on the passage of the Groundwork (G 4:431.21-24) where the ‘semantic core’ (53) of autonomy makes its first appearance. In particular, Bacin aims to reconcile Kant’s parenthetical remark that the will ‘can regard itself as the author [of the law]’ with his tenet that the moral law is not created and has no author. Here, Bacin contends, Kant uses the distinction between the author of a law and its legislator to argue that the rational will is not the author of the moral law, but of its obligatoriness. Accordingly, Kant’s parenthetical remark has the ‘negative and limiting’ (70) function of emphasizing that the will is self-legislating in virtue of not being subject to external influences. In the first instance, then, self-legislation means ‘immediate and independent legislation’ (70), having the moral law as its sole reference.

Bacin then focuses on Kant’s less ‘reflexive’ and more ‘impersonal’ formulations of autonomy (70-71; see O’Neill Reference O’Neill, Nagl-Docekal and Langthaler2004), for example, as ‘the property of the will of being a law to itself’ (G 4:447.1-2). According to Bacin, Kant intentionally echoes St. Paul’s description of the Gentiles as ‘a law unto themselves’ to challenge its rationalist interpretation, according to which it points to a normativity already present in nature together with its obligatoriness. This, Bacin continues, reveals an important difference in conceptions of reason. For rationalists, reason is a law to itself in that it discovers the natural law which functions as a norm for the human being. For Kant, instead, reason does not ‘acknowledge determining motives and put them into practice’ but rather ‘determines its own maxims’: the moral law is ‘given by the will without mediations’ (74). In other words, the moral law ‘does not have reality independently of the exercise of the faculty that it regulates, but emerges from its exercise’: it is ‘“originally acquired” in the determination of the will’ (75). Here, Bacin establishes an illuminating parallel with Kant’s description of the categories of the understanding as ‘selbstgedachte erste Principien a priori unserer Erkenntniß’ (CPR B167, emphasis added), which suggests an ‘immediate availability, on reason’s part, of normative principles that assume their full value in the activity that they make possible’ (75).

Bacin clarifies the claim that moral obligation requires ‘the constitutive participation of the will’ (75) through a note of Kant’s stating that the moral law can necessitate a rational being only if such a being acknowledges the law’s ‘allgemeingültigkeit für jeden Willen, also auch die nothwendige Einstimung seines Willens’ (Refl. 6187, 18:483.11-13). According to Kant, Bacin comments, the law is not an ‘intrinsic normativity’, ‘to be “seen” in order to cognize it, as a normatively neutral fact’; rather, it ‘must be adopted [by the will] as a norm of conduct’ through an act of ‘necessary consent’ (76). This is precisely the role of a legislator in the technical sense of author of the obligation, namely to ‘add their own will to the law’ (76). Rather than involving a simple reflexivity, then, Bacin’s two-level interpretation of autonomy combines ‘an immediate normativity’, the law, and an ‘eigene Gesetzgebung’ that occurs through ‘a necessary consent of the will to the law’ (79). In this way, Kant’s ‘new form of moral rationalism’, which ‘assigns a key role to the will as practical faculty’, can be described as ‘a strongly anti-voluntaristic position expressed largely in voluntaristic terms’ (93).

An advantage of this reading, Bacin claims, is that it lets us detect the presence of self-legislation even where its vocabulary is mostly absent, notably in the second Critique. Bacin interestingly argues that Kant’s presentation of moralisches Gesetz and Sittengesetz (which Bacin equates with the moral law and the Categorical Imperative) in §§6-7 mirrors the Groundwork’s distinction between the two elements of autonomy (‘an immediate law and a legislation through the activity of the will’, 80), before Kant officially introduces the term in §8. Then, Bacin ascribes the absence of the principle or formula of autonomy (as opposed to autonomy as a property of the will) in the second Critique to Kant’s reaction to an objection in Pistorius’s review of the Groundwork, namely that such a principle is arbitrary, especially if compared to the Formula of Universal Law. To clarify the misunderstanding of an acute reader of the Groundwork, Bacin suggests, Kant’s exposition in the second Critique downplays the role of the will and emphasizes, instead, that autonomy involves an impersonal law imposed on rational beings as the source of any moral obligations.

Chapter two ends with an instructive comparison between Kant’s theory and Francisco Suárez’s. Suárez distinguishes ‘the eternity and independence of the natural law’ and the ‘necessity that it be object of a divine command in order to be fully prescriptive through the expression of a will’ (87). Kant, Bacin comments, refuses to tie the second aspect to the divine will because he believes that the prescriptive character of morality can only derive from a will subject to it. Moreover, whereas Suárez employs a traditional juridical-political conception of law, Kant follows a more recent metaphysical conception, according to which laws serve to describe non-contingent regularities.

In contemporary terms, Bacin suggests at the outset of chapter three, Kant can be described as a (proto-)constructivist with regard to moral obligation and as a practical realist with regard to the moral law. Bacin once again presents autonomy as a two-level theory, this time combining moral realism about the law with the non-realist idea that moral obligation depends on the activity of the rational finite will. Such a ‘hybrid’ approach (104), he writes, is anticipated in its basic structure not only by Suárez but also by Jean Barbeyrac (who incorporates realist elements in his voluntarism to address the charge of arbitrariness). The reference to these hybrid theories allows Bacin to highlight Kant’s rejection of the ‘descriptivist presuppositions’ (114) of his moral realist predecessors. In light of this rejection, the doctrine of autonomy becomes also ‘a theory of moral epistemology which holds that the knowledge of the normative content of the moral law […] is knowledge of a constitutive principle of the practical faculty’ (114).

The focus on moral epistemology prepares the transition to Bacin’s discussion of the Fact of Reason. Broadly agreeing with the active interpretation of the Fact as a deed, Bacin argues that the Fact is non-realist and rather should be read in light of Kant’s conception of construction. Accordingly, the Fact involves ‘a determination of the will which represents the moral law in the form of a maxim, thereby corroborating its reality in the practical dimension of the finite will’, in an ‘almost ostensive demonstration of the reality of a rule’ (120-121). After presenting Kant’s original synthesis of realism and non-realism, Bacin undertakes a painstaking disambiguation and contextualization of it in relation to a number of contemporary approaches (Skorupski, Enoch, Korsgaard, Dancy). Then, he elucidates ‘the multi-level combination of realism and non-realism’ (133) of Kant’s theory in analogy with his combination of theoretical realism and idealism (since these are not necessarily mutually exclusive in Kant’s theoretical philosophy).

Chapter four focuses on the introduction to the Feyerabend notes on natural Right, particularly on two notions which make their first appearance there: the end in itself and autonomy. Firstly, Bacin elegantly tackles Kant’s problematic analogy between an end in itself and an ens a se (L-NR 27:1321) by interpreting the former as ‘a constitutive element of practical thinking’ (152). Then, turning to autonomy, Bacin addresses two differences between Feyerabend and the Groundwork: (i) although in Feyerabend Kant does characterize freedom as ‘a law to itself’ (L-NR 27:1322) in the transition from end in itself to freedom, he introduces autonomy only a few pages later and without even mentioning heteronomy; (ii) Feyerabend establishes no link between autonomy and the will. Bacin explains these differences in light of the texts’ argumentative goals. Feyerabend focuses on Right: from this perspective, that freedom is a law to itself only means that Right is a self-limitation of freedom – a claim aimed only at excluding a determination by natural principles, and which does not require the introduction of self-legislation. The Groundwork, instead, needs autonomy as a property of the will in order to account for moral obligation. Accordingly, the transition from end in itself to freedom appears only in the background in the Groundwork (see G 4:428.34f.), and autonomy is eventually mentioned in Feyerabend only because moral obligation could not be explained at all without reference to it. Bacin concludes that the notion of autonomy of the Groundwork is simply ‘circumvented [aggirata]’ in Feyerabend (167). Although by 1784 Kant has already fully developed it, in Feyerabend ‘autonomy is not so much illustrated and justified, but rather applied specifically to […] Right’ (169), and the few unavoidable references to it omit any details irrelevant to the purposes of the course.

Chapter five addresses the question of the alleged ‘disappearance’ of autonomy in the Metaphysics of Morals (particularly in the Doctrine of Virtue), which, Bacin observes, is even more striking given its employment in both practical and theoretical contexts in the Opus Postumum. The main critical target of Bacin’s discussion is Pauline Kleingeld’s recent account of the disappearance of autonomy (Reference Kleingeld and Watkins2018; Reference Kleingeld, Bacin and Sensen2019). Bacin cautiously ascribes the absence of autonomy in the Doctrine of Virtue to two factors. The first is that the arbitrariness objection in Pistorius’s review of the Groundwork might have convinced Kant of the weakness of the implicit political analogy involved in speaking of legislation in a Kingdom of Ends. Since the Categorical Imperative variants only serve to bring its content closer to intuition, Kant might have thought that the principle of autonomy need not be mentioned in the Metaphysics of Morals. The second factor is that the goal of Kant’s Doctrine of Virtue is to articulate his system of duties belonging to ethics, which does not require any reference to his theory of moral obligation. Seen in this light, ‘the disappearance of the “principle of autonomy” is […] an epiphenomenon of Kant’s transition to a positive doctrine of duties of virtue [doveri etici]’ (187). Finally, Bacin characterizes the diminished role of autonomy in the Doctrine of Virtue more positively by arguing that the notion of autocracy, there officially introduced, actually represents an expansion of Kant’s conception of self-legislation, whereby the moral law can be thought of as ‘the law of your own will’ (DV 6:389) (193). Bacin interprets Kant’s ‘autocracy of practical reason’ (DV 6:383) as the ‘property of pure practical reason to apply the law in the individual life, overcoming the obstacle represented by inclinations’ (189).

I cannot do justice to the details of Bacin’s book, so I will only raise a few thoughts that occurred to me while reading it. The first concerns the somewhat surprising final claim of the book: with the notion of autocracy, Bacin writes, ‘Kant’s conception reaches, in its own terms, the territory of personal or individual autonomy, from which it otherwise must be kept scrupulously distinct’ (197). Despite the qualifications, it is difficult to see how this is the case. For one thing, it is hard to pinpoint a single meaning of autonomy in the contemporary sense, let alone to map the overlaps with Kant’s own notion (see Hill Reference Hill2013; Sensen Reference Sensen and Sensen2013). If we assume for the sake of argument that Bacin has ‘freedom of choice’ (13) in mind here, then his claim simply becomes puzzling. Although Kantian autonomy might be conceived as a form of self-determination, it is a moralized and peculiar one, according to which it is the moral law, as opposed to inclinations, that must ultimately determine the individual’s conduct. Instead, contemporary freedom of choice involves a non-moral kind of self-determination.

Secondly, Bacin does not elaborate on how his two-level interpretation fares better than the alternatives criticized in chapter two in dealing with the incoherence traditionally associated with the notion of self-legislation. Doing so would have been especially interesting in light of the recent renaissance concerning duties to oneself (see Muñoz Reference Muñoz and Zalta2022).

Thirdly, chapter two could have explored in more depth the act of consent through which the will necessarily adopts the moral law as its maxim, emphasizing that the will does so in virtue of acknowledging the law’s validity for all rational wills. This is not only supported by the note Bacin cites, but could have led to a richer account of the relation between universalizability and self-legislation.

Fourthly, although Bacin is generally very precise, at points it is not entirely clear whether he is talking about autonomy as a property of the will or about the formula of autonomy. Unfortunately, this is the case particularly in his discussion of the alleged disappearance of autonomy, where the distinction is crucially relevant.

Finally, although a monograph can hardly satisfy all its readers with regard to what it covers and how, Bacin’s choice in these respects is slightly disappointing in some cases (especially since parts of chapter three feel a little repetitive). For example, he could have provided a less piecemeal and more sustained comparison between Kant’s conception of reason and that of his rationalist predecessors, or suggested an argument on Kant’s behalf for why voluntarism necessarily implies arbitrarism (the point denied by Barbeyrac). As to the sources, Bacin’s very few words on the clearer reappearance and even theoretical extension of autonomy in the Opus Postumum stir the reader’s curiosity only to frustrate it (although the book’s focus on Kant’s practical philosophy and considerations of length could be cited in his defence).

None of the critical remarks above detract from the overall scholarly value of Bacin’s book. Besides containing sections that deserve the attention of anyone involved in the contemporary debate between moral realism and anti-realism, the book constitutes a highly significant contribution to the literature on Kant’s practical philosophy in general, and will undoubtedly be an important source for any serious future works on Kantian autonomy in particular. One can only hope that one day the book will be made available to English readers as well.Footnote ²